A "new" take on Linux-on-iMac

[fox]

After all the issues I was having with my 2015 5k imac, I gave up on it as a vehicle for Linux and bought a 2019 refurb. This was a bit of a gamble, as I hadn't seen a lot of postings on problems with it, at least with ones I couldn't solve. The good news is it has no kernel problems; both the 5.4 and 5.8 series boot up quickly. The bad news is that my internal wifi (Broadcom BCM4364), audio and microphone are not recognized, nor are drives plugged into the thunderbird ports. So I had to buy a wifi dongle (Linksys wusb6300), compile the driver (not difficult), and continue to plug in external speakers via another dongle (requiring two usb ports). I have yet to buy a microphone, so I can't do Zoom meetings on the Linux side. (Not a big deal, as it's a dual boot with MacOS.) And I can plug things other than drives into the thunderbolt ports using a thunderbolt to usb3 adapter. Using this approach, I have as many as 6 usb3 ports on the iMac, and I already need 5 of them (1 for speaker, 1 for audio dongle, 1 for wifi, 1 for keyboard/mouse, 1 for scanner).

For some reason, Ubuntu 20.04 kernel panics when more than the 4 usb ports are used, but Ubuntu 20.10 is fine. So that is what I am now using.

Bottom line on iMac with Linux. I have had three 27" iMacs: 2011, late 2015 5k, and now 2019 5k. All have AMD graphics. I have tried not only Ubuntu, but several other distros on them. None of them are flawless, but the earliest of them is nearly so. The internal speakers and mic work flawlessly and the internal wifi works with drivers in the Ubuntu repositories. Thunderbolt drives can be seen and read. The only thing that doesn't work is brightness control, but the native brightness is fine, so I never looked too hard for a solution. The only problem with the 2011 iMac is on the Mac side - the current version of MacOS isn't supported and the latest it runs (High Sierra) will no longer be supported after November.

The late 2015 was the most problematic. The internal speakers don't work and thunderbolt drives cannot be seen, but the mic works and the internal wifi works with drivers in the Ubuntu repositories. Brightness control works. But the big problem, the one I could never solve, is the kernel booting problem. Any kernel from 5.3 up takes several minutes to boot and changes to monitor resolution are glacial, as is the shutdown sequence. I was limping along with the Ubuntu 18.04 LTS kernel (4.15), but something happened during a MacOS update that messed up grub and I could never fix it, so it meant choosing to boot the MacOS or the distro at the top of the grub list (and those were the only choices) through the Mac booter.

The 2019 has more driver support problems than the 2015, but none that cannot be fixed with inexpensive external dongles. And I'm hoping to see BCM4364 support soon, which will free one of my usb ports now using a wifi dongle. In addition to the dongle problems, support for brightness control depends on the kernel you use. It is supported in the Ubuntu 5.4 LTS kernel, but not the Ubuntu 20.10 5.8 kernel. However, the latter doesn't kernel panic when more than 4 usb ports are occupied, so that's what I am going with. As for brightness control, it works with a tiny app called appropriately "Brightness Controller", which is in the repositories. The 2019 iMac will be supported on the Apple side for many years to come, so I expect to be using this computer for both Linux and Mac for a long time.

[Jason]

The Broadcom issue is a common one with Linux distros from what I understand unless you mean what you're experiencing is specific to the model you're using. Some distros include the Broadcom support right away, most you have to add it. If I recall, elementary OS includes it out of the gate.

You said, "I was limping along with the Ubuntu 18.04 LTS kernel..." I resent that. That kernel isn't limping. It will be supported until 2023. The website is running off of it and security updates and bug fixes are regularly applied. But yeah, for a desktop, it'd be nice to have a newer kernel with support for newer hardware, but it's not necessary unless you lack support for something you need. I'm sure when you said "limping", this is what you meant.

Thank you for your observations. I'd like to see more people running Linux on Mac hardware and your posts will give them inside information that maybe can be found only here. That'd be a nice edge up for the Forum. It'll especially be interesting to see what happens when Apple hardware moves to use the ARM processors. Debian has an ARM-based version and some other distros do (I believe that Ubuntu does which should bring broader support), but many don't.

[fox]

The Broadcom issue I am referring to here is specific to the model in the 2019 iMac (BCM4364). There doesn't seem to be a driver available for it in Linux and the usual packages required to install Broadcom wifi drivers don't work on this one. I'm hoping that a driver is eventually released for it, and hopefully packaged in Ubuntu. In the meantime, my usb dongle is quite fast, and other than taking up a port, there is no downside to using it.

The limping along was referring to use of the 4.15 kernel in Ubuntu 20.04; I have nothing against version 18.04 but I wanted the updated distro. The 4.15 kernel doesn't update automatically in 20.04, which meant that I had to find out when new 4.15 updates were released by Ubuntu and manually install them. I could have even lived with that for a few years until the Mac update scuttled my grub and I couldn't fix it. I still don't understand what happened with that update, but after it I lost all ability to access Thunderbolt drives, and that meant I could no longer use my Linux Mint 20 partition, which was on that drive.

I do post the Mac-related threads in our forums in the hope that Mac users are helped by them. I don't expect that many of our PLUG members are interested in them, but yes, I'm sure they bring outsiders to our forums. It would be great if for once, a Linux-on-Mac user will post a solution in our forums to one of the Mac-related problems I have had.

Regarding the Apple Silicon (ARM-type) Macs that are due out soon, I thought about waiting for one of these, but something I read in a Linux magazine suggested that it could be awhile before they are supported by Linux distros. Also, the first Apple Silicon iMac due out is a 24" model, and it has been suggested that a 27" model wouldn't be out for at least a year. I am now used to a 27" display, and don't want to go back to a smaller one. The Silicon iMacs, when they come out, are supposed to be lightning fast, but the 2019 model I bought is already lightning fast. So was the 2015 model for that matter, so speed has never been the issue.

[Jason]

I'm actually kind of jealous of your Macs. Some day I'll get one but, and I know it's weird for me to say, I probably will run the Mac OS on it.

Regarding running Linux on Macs, have you looked to see if there is a forum specifically related to that? I'm curious. There might not be a lot of people doing it compared to on PCs but around the world, even just the English-speaking world, I'm sure it would add up to a significant number.

[ssfc72]

Nice catch on that 2019 iMac, Mike.  Have you re-homed the 2015 iMac?

[fox]

I seriously debated about selling or trading in the 2015 iMac, but ultimately decided it would make more sense to "re-home" it with my wife as a 100% MacOS computer. All versions of the MacOS will run on this computer, including the yet-to-be-released Big Sur. So it has a long future as a Mac computer. I don't intend to put Linux on it again, although just for fun, I might test a distro with a kernel newer than 5.9 to see if it will boot it without the several minute delay.

[fox]

I'm actually kind of jealous of your Macs. Some day I'll get one but, and I know it's weird for me to say, I probably will run the Mac OS on it.

I don't think that's weird at all. If you've never had the opportunity to run MacOS, it's a good experience. (Much better than Windows!) The only serious issue I ever had with MacOS is its lack of customisability. It was actually easier to customize in the past, but it is much more locked down now.

Regarding running Linux on Macs, have you looked to see if there is a forum specifically related to that? I'm curious. There might not be a lot of people doing it compared to on PCs but around the world, even just the English-speaking world, I'm sure it would add up to a significant number.

Ubuntu has such a sub-forum. I haven't found it to be of much help. I have had better luck with just Googling my problem and going to wherever that takes me. I've already done that for wifi and audio problems, but no solutions emerged.